TM 5-5420-280-23&P
0010 00
Hydraulic System Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
10. BOTTOM BRIDGE HALF WILL NOT MOVE ON LAUNCH BOOM (L16-H) OR (R7-H) (CONTD)
Step 5. Check that rear pin wheel drive hydraulic motor rotates.
If hydraulic motor will not rotate, replace hydraulic motor. Refer to WP 0084 00.
Step 6. Check for damaged or locked-up rear pin wheel drive stop cylinder.
Repair or replace damaged stop cylinder. Refer to WP 0085 00.
END OF TESTING
11. SECONDARY BOOM CYLINDER WILL NOT RAISE OR LOWER (L9-H), (L13-H) OR (R10-H), (R14-H)
Step 1. Check for bent or damaged secondary boom rollers or bracket.
a. Replace bent or damaged secondary boom rollers. Refer to WP 0098 00.
b. Replace bent or damaged secondary boom bracket. Refer to WP 0098 00.
Step 2. Check for damaged supporting boom cylinder.
Replace supporting boom cylinder. Refer to WP 0099 00.
Step 3. Check that KY1, KY14, and KY15 hydraulic control valve solenoid LED lights are lit when
action button 1 during launch, or action button 2 during retrieval is depressed.
NOTE
Limit switch KA6 stops secondary boom and once lowered, actuates
launch boom to go up.
If all lights are lit on control valve solenoids, check limit switch KA6 to see if damaged or
out of adjustment. Adjust or replace limit switch KA6 (WP 0056 00).
Step 4. Check for damaged control valve KY1, KY14, and KY15.
a. Manually operate control valve solenoid by pressing down on KY1 solenoid button and
KY14 to raise or KY15 to lower secondary boom.
b. If control valve operates refer to malfunctions 11 or 41 in Electrical Troubleshooting
c. If control valve will not operate, replace control valve KY1, KY14, or KY15. Refer to
END OF TESTING
12. LOWER BRIDGE HALF WILL NOT MOVE TO COUPLING POSITION (L14-A) AND (L15-A) OR (R9-A)
Step 1. Perform Launch Boom Will Not Lower or Raise malfunction 7 if launch boom will not lower
or raise.
Step 2. Perform Lower Support Boom Cylinder Will Not Extend or Retract task 9 if lower support
boom cylinders will not extend or retract.
Step 3. Check Electrical System Troubleshooting. Refer to WP 0008 00.
END OF TESTING
13. LAUNCH BOOM WILL NOT MOVE TO PRE-COUPLING POSITION (L12-A) OR (R9-A)
Step 1. Perform Launch Boom Will Not Lower or Raise task 7 if launch boom will not lower or
raise.
Step 2. Perform Lower Support Boom Cylinder Will Not Extend or Retract malfunction 9 if lower
support boom cylinders will not extend or retract.
Step 3. Check Electrical System Troubleshooting. Refer to WP 0008 00.
END OF TESTING
